Arylsulfatases A and B, enzymes shown to be elevated in human osteoarthritic cartilage, were isolated and purified from this tissue. The enzymes have also been isolated from human chondrocytes grown in culture. These enzymes will be purified to homogeneity and their mechanisms of action determined. Physiological substrates and regulators of their activities will be investigated. An activator of arylsulfatase A activity in cartilage will be sought. The relationship between arylsulfatase B and chrondro-4-sulfatase will be examined. The role of arylsulfatase B' in cartilage will be looked at. Since osteoarthritis prevails in older individuals, we propose to identify, isolate, and purify the enzymes responsible for the desulfation of chondroitin -6- and keratan sulfates. The substrate for these enzymes will be identified and the phosphate content determined. Phosphate moieties may serve as "on/off" signals for the onset of catabolism. Differences in specific recognition markers on these enzymes for receptor-mediated uptake or lysosomal packaging will be studied with a view to determining whether alterations or deletion of these markers could account for increased enzyme activities in osteoarthritis. Chrondrocyte cultures, established from normal and osteoarthritic human articular cartilage will be employed as sources for enzyme isolation. They will also be used as test systems to examine and compare the effects of exogenously added components of synovial fluid and other metabolites on sulfated proteoglycan metabolism. Proteoglycans isolated directly from the normal and pathologic tissue will be compared with those produced in culture. HPLC will be used to monitor catabolic products of proteoglycans produced by normal and osteoarthritic chondrocytes or cartilage slices with a view to finding differences. In the broadest sense, this research is directed toward a better understanding of the regulation of proteoglycan metabolism under different physiological conditions with a view to facilitating early diagnosis and providing a rationale for non-surgical therapy in osetoarthritis.